Shares of Chegg (CHGG -2.19%) fell as much as 11.5% early Friday, then settled to close down 2.19% after a Goldman Sachs analyst downgraded shares of the online education platform.Goldman thinks AI will be a headwind for CheggIn a note to clients this morning, Goldman analyst Eric Sheridan lowered his rating on Chegg to sell from neutral, and also reduced his per-share price target on the stock to $8 from $10. To justify his relative bearishness, Sheridan said he's reducing his revenue estimates for Chegg g ...